Background: The consistency of fixed airflow limitation status during treatment in patients with asthma is unknown. Objective: The objective of this study was to determine the consistency of fixed airflow obstruction (FAO) status during treatment and effects on treatment response. Methods: This post hoc analysis from a 12-week study (NCT00652002) assessed patients aged 12 years or more with moderate-to-severe asthma randomized to twice-daily budesonide/formoterol (BUD/FM) via pressurized metered-dose inhaler (pMDI) 320/9 μg, BUD pMDI 320 μg, FM 9 μg via dry-powder inhaler, or placebo. FAO status was assessed postbronchodilator at screening and after study drug administration at weeks 2, 6, and 12 via the forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) ratio < lower limit of normal (LLN) (FAO+) or ≥ LLN (FAO−). Patients with persistent FAO− and FAO+ retained their screening FAO status at all visits. Patients with inconsistent FAO changed categories at least once during the study. Assessments included early withdrawal due to predefined worsening asthma events (PAEs), lung function, and symptoms. Results: Of 386 patients, 29% had persistent FAO+, 31% inconsistent FAO, and 40% persistent FAO−. PAEs were lowest in the FAO− group overall and with BUD/FM treatment in patients with FAO+ and inconsistent FAO. Baseline demographics and treatment responses of the inconsistent FAO group were most similar to the FAO+ group. The greatest improvements in asthma control days and use of rescue medications were seen with BUD/FM treatment, regardless of FAO status. Conclusions: Approximately one third of patients with moderate-to-severe asthma in this study had inconsistent FAO, and their treatment responses were most similar to patients with FAO+. Regardless of FAO status, patients treated with BUD/FM experienced the most improved treatment responses and fewest withdrawals due to PAEs.
Tashkin, D. P., Moore, G. E., Trudo, F., DePietro, M., & Chipps, B. E. (2016). Assessment of Consistency of Fixed Airflow Obstruction Status during Budesonide/Formoterol Treatment and Its Effects on Treatment Outcomes in Patients with Asthma. Journal of Allergy and Clinical Immunology: In Practice, 4(4), 705–712. https://doi.org/10.1016/j.jaip.2016.02.014